Peppered Moth Simulation

Peppered Moth Simulation Name ______

Objectives:

Describe the importance of coloration in avoiding predation Relate environmental change to changes in organisms Explain how natural selection causes populations to change

Materials

Light Bark Paper Clock with Second Hand Dark Bark Paper 10 Light Moths Colored Pencils 10 Dark Moths Forceps

Purpose: In this lab, you will simulate how predators locate prey in different environments. You will analyze how color affects and organism's ability to survive in certain environments.

Industrial Melanism is a term used to describe the adaptation of a population in response to pollution. One example of rapid industrial melanism occurred in populations of peppered moths in the area of Manchester, England from 1845 to 1890. Before the industrial revolution, the trunks of the trees in the forest around Manchester were light grayish-green due to the presence of lichens. Most of the peppered moths in the area were light colored with dark spots. As the industrial revolution progressed, the tree trunks became covered with soot and turned dark. Over a period of 45 years, the dark variety of the peppered moth became more common.

Procedure:

1. Decide who will be the “predator” and who will be the timekeeper. 2. Place the light bark paper on the lab table. If you are the timekeeper, scatter 10 light moths and 10 dark moths on the sheet of paper while your partner looks away. 3. The “predator” will then look back and try to pick up as many of the moths as they can in 5 seconds using the forceps. Record the numbers on the chart. 4. Replace the light bark paper with dark bark paper. If you are the timekeeper, scatter 10 light moths and 10 dark moths on the dark bark paper. The predator repeats the hunting procedure for 5 seconds. Record data. 5. Change the roles of timekeeper and hunts and repeat steps 2-4. Record data.

Starting Population Number Picked up Trial Background Light Moths Dark Moths Light Moths Dark Moths 1 (student 1) Light Bark 10 10

2 (student 2) Light Bark 10 10

3 (student 1) Dark Bark 10 10

4 (student 2) Dark Bark 10 10

Analysis 1. What did the experiment show about how prey is selected by predators?

2. What moth coloration is the best adaptation for a dark background? How do you know?

3. What would you expect the next generation of moths to look like after trial 1? What about the next generation after trial 3?

4. How does the simulation model natural selection?

5. Examine the table and construct a graph. Plot the years of the study on the X-axis, and the number of moths captured on the Y axis. You should have 2 lines on your graph - one for light moths, and one for dark moths.

# of Light # of Dark Year Moths Moths Captured Captured 2 537 112 3 484 198 4 392 210

5 246 281

6 225 337

7 193 412 8 147 503 9 84 550 10 56 599

6. Explain in your own words what the graph shows.